Aggressive tackling of Covid-19 cases needed to prevent 2nd wave: Research paper
A working paper by a team of researchers at the Indian Institute of Science (IISc) and Tata Institute of Fundamental Research (TIFR) suggests that there will be a second wave of Covid-19 infection unless new cases are aggressively traced, localised and isolated.
The paper, released on Sunday evening, looks at various scenarios in which a lockdown is lifted in cities affected by Covid-19 infections. It also considers the most restrictive scenario when the lockdown continues to be imposed indefinitely: lockdown until May 31; lockdown until May 3 as currently planned etc. In all cases, researchers have considered infected cases are being isolated with 90% compliance.
Researchers have then modelled the impact of nine interventions on infections in Mumbai and Bengaluru. These interventions include only case isolation; social distancing of those aged 65 years and above; lockdown for 26 days; lockdown for 40 days; lockdown continues; phased emergence from lockdown with various restrictions. Based on demographic data of Mumbai and Bengaluru, the team found that if the lockdown were to continue indefinitely, the number of Covid-19 fatalities in Mumbai till September are likely to be a fraction compared to no intervention scenario. The fatalities reduce to 530 as compared to 27790 in the no intervention scenario. If the lockdown were to be lifted on April 20 and people returned to normal activities, the number of fatalities will still rise, but slowly. Even if the lockdown were to be lifted only after May 3, the relaxation of restrictions will lead to fatality numbers going as high as with no-interventions, but gradually. “This delay may allow better mobilisation of resources for aggressive testing, tracking, and containment that can change the course of the epidemic,” the paper said.
Bengaluru offers a similar scenario. If the lockdown were to continue indefinitely, the number of Covid-19 fatalities in the city are likely be far fewer: 30 compared to 21,200 in the no intervention scenario. These projections were made until September 2, 2020, for Mumbai and July 22, 2020, for Bengaluru, according to Rajesh Sundaresan, corresponding author of the paper.
The team of researchers has arrived at these trends based on a simulation of the infection spread in Bengaluru and Mumbai using a model, which builds a fine-grained replica of a city, and mimics various interaction spaces, such as households, schools and workplaces, according to a statement by IISc.
“If there are 10 million people in Bengaluru, the city’s model also has that many individuals,” said Sundaresan, Professor at the Department of Electrical Communication Engineering at IISc, in the statement. He added that the model also takes into account population densities, age distribution, household size distribution, commute distances and several other parameters.
“We have to increase identification of cases by active case finding and enhanced testing, ensure isolation and quarantine and continue proper physical distancing, cough etiquette, respiratory hygiene. We have to get used to the new normal now or cases will rise steadily. Plans will have to be developed for migration, transit inter and intra districts and states after lockdown also,” said Giridhar R Babu, professor and head, Lifecourse Epidemiology, Public Health Foundation of India.